Structural element

ABSTRACT

A structural element (10) for forming a panel, with an upper plane (12) and lower plane (14) which are parallel and deformed along their plane at intervals by pods (16) which extrude toward the opposing plane with their internal faces mating to one another.

FIELD OF THE INVENTION

The present invention relates to a structural element, and morespecifically the manufacture and use of a structural element to formsheets, panels or pallets with a high resilience to external tensile andcompressive forces whilst maintaining mechanical stiffness.

BACKGROUND OF THE INVENTION

A panel, it its simplest form, may comprise of a sheet of material. Itcan be single ply or multi-ply. The desirable attributes of the panelwould depend on the situation it is required for. For instance, a panelused as a covering would be expected to be less rigid than a panel usedfor a roof and a panel used as a platform which people stood or walkedupon would need to have resistance to lateral point stresses in additionto being rigid.

By increasing the thickness of the panel (or by adding more sheets andvarying the gap between those sheets) the same material may be used fora panel in which the rigidity and strength can be varied. An increase inthickness of the material will increase the amount of material used andthis in turn this would increase the weight and costs of the material.Instead just varying the space between the sheets or plies can achievesimilar strength or rigidity changes, but without the considerableincrease in material costs—only the material cost of any additionalspacing materials would be incurred.

It is known to use these techniques to increase the strength of a panelwhilst minimising the increase in material used. Other techniques arealso known. These include varying of the shape of the panel, such asusing corrugations, or by using composites where different materials arecombined, such as foam filled fibreboard. Another method is to combinethese techniques, for example where a shaped material forms the internalstructure of a panel. These methods are not without their own issues:such structures may result in unidirectional strength, or additionalcosts in the manufacture of the complex structures, and more costlyrecycling in the case of composites, and this can outstrip the benefitof the material saving.

It would therefore be desirable to create a structural element where,compared to a sheet of material, the strength can be increased withoutthe addition of further material, and thus weight. It would also bedesirable for the structural element to be versatile, for example nothaving a preferred orientation for its use. It would also be desirablefor the structural element to be easy to manufacture.

SUMMARY OF THE INVENTION

The present invention provides a structural element made from sheetmaterial that is deformed at intervals along its length and width toprovide pods that protrude from the plane of the sheet where the wallsof the pods slope obliquely relatively to the plane of the sheet.

The present invention also provides a structural panel consisting of twoouter sheets that act as the tensile and compression chords, both withmultiple inwardly orientated pods throughout the panel and who's apexesare joined together, which have a close proximity one to another inorder to be mechanically interdependent creating a double depthspace-frame lattice type matrix where loads placed on the panel'ssurface are resisted and transferred through the chords and with thepods acting as interconnecting diagonal braces.

In a preferred aspect of the present invention at least two sheets areformed with such pods, and two of the sheets are juxtaposed to eachother in mirror-image, or facing, fashion, with floors of the podsengaging in contact zones.

Preferably the two engaging sheets are of similar (or substantiallyidentical) size and/or shape.

Preferably the two engaging sheets are joined in the contact zones toprovide a unitary element formed of the two sheets. The join may be byany known method or means, such as an adhesive joint, a weld or by useof folded or rolled flanges, or by combinations of such, or other, knownjoining methods.

Preferably the pods are frusto-conical in shape.

Preferably the floor of the pod is circular.

Preferably a part of the floor or base of one or more of the pods may beremoved to enhance the lightness of the finished element. Preferablythis is done leaving a flange, more preferably an annular flange, e.g.by removal of a central disc.

Preferably the contact or the jointing between the two engaging sheetstakes place at or along the flange(s).

The relationship in the individual pod geometry, and the strength of theresulting structural element, can be guided or influenced by the ratiobetween the pod opening's dimension (at its intersection with thesheet—a diameter when round) and the depth of the pod. This geometry,and the degree or direction of influence, is governed by the extent ofthe stretch of the material resulting from the deformation, i.e. theamount or extent of ellongation of the selected material. In the case ofsteel, there can be a significant degree of stretch before the materialreaches a yield point, or a point at which additional strength is notadded, and that extent of stretch can be varied by controlling thestretch, for example through use of variable formers, multiple passes orheated formers. However, for cost efficiency it is preferred to use justa single pass through a press—reduced processing time results in reducedmanufacturing costs, and thus reduced commercial prices or increasedprofit margins.

For steel, it is preferred that the extent of stretch of the materialfrom the sheet used to form the pod is about 30%, and more preferablybetween 20 and 40%. The extent of stretch can be calculated as 30% whenthe development length through the centre of the formed pod, from sheetedge to sheet edge, is 1.3× the diameter of the pod (at its intersectionwith the upper surface of the sheet.

30% is a preferred extent of stretch for a single pass pressing process.

If there are multiple passes through the press then this percentage maybe different—for example the stretch can generally be longer withoutapproaching a yield point. Nevertheless, single passes are moreeconomic, and are thus preferred for mass production of structuralelements of the present invention.

A variety of methods or means may be adopted to join the contacting podstogether—for example different methods at different pods, or the same ateach pod, but with different structural elements having differentmethods of jointing. The present invention might then comprise a productcomprising two different forms of structural element, both formed inaccordance with the present invention, e.g. a pallet top and palletlegs, the pallet top formed using one form of structural element and thelegs being formed from a different form of structural element, but bothforms being in accordance with the present invention.

Preferably loads when applied transverse to a top plane of thestructural element, e.g. to a top sheet thereof, are transmitted to abottom or different plane of the structural element, e.g. to a bottomsheet of the structural element. Typically this will occur since loadswhen applied to a first sheet of the structural element are transmittedalong or through the surfaces or structure of the pods of that firstsheet to the opposing pods on the second sheet through the jointing orcontact therebetween, the load thus transferring to the bottom or othersheet of the structural element. The structural element thus has similaror comparable load handling characteristics to a space frame.

Preferably loads when applied to a plane of a sheet of the structuralelement are transmitted along the surfaces of the pods in multipledirections such that the load is distributed throughout the structuralelement. This can offer greater advantages than a space frame since in aspace frame the loads are handled generally along the structuralmembers, whereas in the present invention they can additionally becarried circumferentially and radially through the walls of the pods.

Although in a first embodiment the pods may be generally frustoconical,thus having a predominantly circular section (and thus only one side—aconical side), in other preferred embodiments one or more of the pods,and preferably each pod, can have more than one side. It is preferredthat these sides are each composed primarily of a flat area, althoughthey might instead be fully curved, albeit not at a radius that wouldcreate the full cone, i.e. a larger radius than that for assuming acapsule (2 side), triangle (three side), square or rectangular (fourside) or other polygonal shape (more than 4 sides, or non-regularshapes). The sides can also be corrugated if desired for addedcompressive rigidity for the structural element.

It is preferred that at least one of the sides of a pod meets one ormore adjacent side of that pod along a generally linear region so as toform ridges in the shape or surface of the pod. The ridges perform astiffening function, as would the above-mentioned corrugations. Theridges can be relatively square edged, i.e. with an external radius ofless than 2.5 mm, or 5% of the length of the longest side of the pod,measured at the outer surface, or mouth, thereof—e.g. at the top planeof the sheet in which it is formed, or it may be more rounded so as toreduce stress concentrations. In that regard, zones of the pod outsidethe flats are more preferably curved.

In one arrangement of the pods, the mouths of the pods are substantiallysquare and the pods occupy substantially the whole of the upperreference plane (for an upper sheet), just leaving a grid for that upperplane where the pods meet at their upper edges. The grid defines lines,the lines forming ridges in the reference plane. The ridges enhance thestiffness of the element, and leave a small area of contact between thestructural element and any product placed thereon—that can beadvantageous in some circumstances.

Preferably the joints between the adjacent pod floors are substantiallyin the central 15 area of the panel. In some arrangements the jointsbetween the pod bases are off-centre.

In some arrangements at least one of the engaging sheets is flat with nopods.

Preferably the structural element has a high resistance to forcesapplied to a sheet thereof, normally (transversely) to the plane of thesheet. Likewise it can have a high resistance to forces acting on it inany direction. The geometry of the structural element allows it todistribute these forces efficiently through the material from which itis composed so that the forces are widely dispersed and hence attenuatedrather than acting along discrete lines of force or in discrete zones ofstress.

Preferably the structural element is formed from metal. Many metals canprovide the desirable toughness and durability, and can providelongevity and resistance to impacts. Steel and aluminium, or theiralloys, are preferred due to their relatively low cost. Copper, brass,tin, nickel, titanium and magnesium alloys may be likewise be suitablefor certain specialised applications.

Preferably the pods are formed in the sheet using a press.

Instead of metals, the structural element may be formed from a plasticsmaterial—typically a mouldable and/or formable plastic. The structuralelement might alternatively be made from a fibrous or a cellulosematerial such as paper or card.

The structural element might be moulded rather than formed. For ease andspeed of manufacture, however, it is preferred for the structuralelement to involve a forming process for forming the pods. Formingprocesses are particular manufacturing processes which make use ofsuitable stresses (like compression, tension, shear or combinedstresses) to cause plastic deformation of the materials to producerequired shapes. Some examples of forming processes are forging,extrusion, rolling, sheet metal working, rotary swaging, thread rolling,explosive forming and electromagnetic forming.

In some embodiments, the pods leave spaces between them in the materialof the plane of the or each sheet around the pods. This is necessarilythe case where the pods are round. It is possible for those spaces to beleft flat. This minimised the degree of working required for forming thesheet. However, the material of the plane of the sheet around the podscan instead be provided with strengthening portions, such ascorrugations, ridges or folds. These can improve or increase the bendingstiffness of the structural element, an effect that is increased if theyare not all monodirectional (i.e. all extending in the same singularorientation).

Preferably the pods are arranged in rows on the plane of the sheet. Auniform arrangement assists with the efficiency of the forming process.In a preferred arrangement adjacent rows are staggered. This isparticularly preferred, albeit non-essential, for round pods or fortriangular pods, or for pods having more than 4 sides. That is becauseit allows a more dense packing of the pods onto the sheet surface, andalso a non-continuous longitudinal and transverse beam pattern along thelength of the structural member (the beams instead become diagonal),thus often increasing the stiffness of the structural element in itsnormal use configurations.

Preferably the structural element is generally planar or flat, althoughit can be formed to have profiled shapes, e.g. for vehicular bodywork.It can also have profiled or variable thicknesses. See FIG. 8E—views i)to v) for examples, i) being flat, ii) having a curved top, iii) havinga curved top and bottom, iv) being convex (or concave) and v) beingwavy.

The structural element may even have one or more flat or planar area andone or more curved area.

Preferably the connected pods form substantially diamond beam formationswith adjacent connected pods such that multiple diamond beam structuresare formed throughout the structural element. These will occur in thenegative space immediately between pairs of joined pods. Where the podsare square or triangular, or where polygonal with interfacing sides,such as with intermeshing regular hexagons, or a mix of aligned hexagonsand intermeshing rhombuses, these diamond beam structures can beelongated to define a grid of diamond beam structures.

The substantially diamond beam structure can be such that there is aflattened, rather than pointed, top or bottom. As such the apices of thediamond beams in contact with the plane of the sheet are truncated, thusforming a frustum. More preferably the diamond beam is a bifrustum.

Preferably the frustum's minimum width on a given diamond beam is nomore than half the width of the diamond at that section, and morepreferably no more than one third of the width of the diamond at thatsection. Areas of the beam away from the minimum frustum width part,—i.e. where the pods are round, can be wider than that.

Preferably the height of the diamond is no more than double the width ofthe diamond—from frustum to frustum where frustums are present.

Preferably ribs are provided on the panel surfaces where there is anextended gap between the diamond beams. This can be, for example, wherethe apex of the diamond beam is not coincident with the chords ordiagonals formed by the pods, i.e. on the frustums, or where thefrustum's minimum width exceeds the above half width or one third widthof the diamond at that section, or elsewhere where there is an extendedflat on the panel. The ribs can be directed across the gap, for exampleperpendicular to the pod edge, or parallel to the pod edges, orotherwise. In place of ribs, these reinforcements may be corrugations ordomes or other deformations for resisting crumpling, bending or otherdeflection or failure of these areas.

The depths of the pods will typically be in the range 7 to 20 mm.

The side angles preferably are predominantly between 30 and 80° from theplane of the upper or lower surface of the structural element.

Preferably approximately 30% of the surface of the sheets remain in thereference plane—the pods account for the remaining 70%. Preferably thatreference plain includes no less than 10% of the sheet, and no more than40%. Any ribs included in those surfaces are included in thepercentage—only the pods/cones are not included.

In many embodiments the pods are conical. This shape will result in aresistance to twisting or coiling of the panel, especially if the podsare arranged in staggered and intermeshing rows. Round pods also causewebbing to be present between the pods and the diamond beams (wherepresent). If that webbing is also corrugated or ridged, this furtherincreases the resistance to twisting of the panel.

Foam can be provided between the surfaces of the panel. This can thenoffer insulation or soundproofing properties

Preferably the materials used for the panel have a strength to weightratio of about, or at least, 10:1 compared to conventional wooden orplastic equivalents. In this regard, steel is a preferred material as itis commonly 10 times stronger than wood and plastic on a weight forweight basis.

The present invention also provides a method for producing a structuralelement comprising providing a sheet material, deforming deformed it atintervals along its length and width to provide pods that protrude fromthe plane of the sheet where the walls of the pods slope obliquelyrelatively to the plane of the sheet, providing a second sheet,deforming it at intervals along its length and width to provide podsthat protrude from the plane of the second sheet where the walls of thepods slope obliquely relatively to the plane of the second sheet,juxtaposing the two sheets such that the pods are juxtaposed to eachother in mirror-image or aligning fashion and such that floors of thejuxtaposed pods engage in contact zones, and joining the sheets in thecontact zones to provide a unitary element.

Preferably the deformation is automated.

Preferably the two sheets are deformed at the same time.

Preferably the deformation is a single pass pressing action. A pressmachine can be used to do the deformation operation.

The deformation may be carried out using, or in conjunction with, anyone or more of the following operations: bending, stamping, punching,blanking, embossing, bending or flanging.

The manufacture can be via an extrusion or pulltrusion technique,although pressed or moulded forms are more preferred.

The method can be a single pass manufacture technique.

The method preferably uses a coil fed high speed production line, forexample producing around 20 pallets per minute. High speed includes flatsheet feed speeds in excess of 10 m per minute.

Preferably the sheets are joined at the contact zones by welding. Otherjointing processes may also or instead be used, such as folding flanges,crimping or gluing.

Preferably at least parts of the floors of the pods are removed when, orprior to, the two sheets/contacting pods are joined together. Thiscreates holes and is particularly beneficial for pallet applications,and other non aerodynamic applications, so as to allow reduced weightand easier washing. Other applications, however, might not benefit fromsuch holes. For example, truck body panels would preferably not havesuch holes, especially where the panels are external body panels—justthe pods may provide an aerodynamic benefit, but adding the holes wouldcreate an aerodynamic disadvantage.

Preferably the sheet material is plastically deformable.

Preferably the sheet is locally stretched when the pods are formed.Forming the pods thus does not change the mass of the sheet, but it addsdepth to the sheet.

Preferably the pods create a depth for the panel that is at least 20times the thickness of the material of the sheet, and more preferably atleast 50 times that thickness, and often more than 80 times thatthickness.

In one embodiment the depth is at least 88 times the thickness of thematerial of the sheet. In another embodiment the depth is at least 160times the thickness of the material of the sheet.

Preferably the structural element is a panel used to carry loads uponits outer surface—i.e. over the mouths of the uppermost pods.

Preferably the structural element forms a part of a product. As such itmay be a panel that is raised off the ground by a base, which base maybe formed by legs, skids or otherwise, the base being for suspending thepanel above the surface of the ground.

One example of this kind of product is a pallet. Another is askateboard, where the base is a pair of wheel assemblies.

The base may be an integral part of the structural element—e.g. beingmoulded onto or formed from one or both of the joined sheets.Alternatively it is a component fitted to the panel, for example afterthe panel is formed.

The base for the structural element may take the form of a cup shape,and it may be pressed from one or both of the joined sheets.

In an alternative arrangement, the base for the structural element maytake the form of a half cup shape—cut in half vertically. Again it maybe pressed from one or both of the joined sheets.

Preferably the base allows nested stacking of corresponding pallets,with the bottom of the base of a first pallet fitting into an opening inthe top of the corresponding base of a second pallet. Cup and half cupbases readily achieve this function. Other base designs offering thisfunction—often featuring pallet legs, are also well known in the art ofmoulded pallets. Such designs can be incorporated into the presentinvention by adding such legs or bases to pallets featuring thestructural element of the present invention as the top thereof.

Preferably the base is shaped such that when multiple pallets arestacked, the bottom of the base of a first pallet will sit below theupper plane of the structural element of the pallet below it. This ispartial nesting. More preferably the bottom of the base of a firstpallet will sit below the lower plane of the structural element of thepallet below it. This is full nesting and it allows a more compressednesting of the pallets, which is important to reduce the space occupiedby empty pallets which are being stored or transported. Preferably thenesting can be such that the underside of the structural element of thefirst pallet is located close to the top side of the structural elementof the second pallet—i.e. closer than the thickness of the structuralelement.

In an alternative arrangement the base of the structural element is oneor more skid. The skids might be welded onto the structural element. Inanother arrangement the skids are adapted so as to be detachable (e.g.bolted or clipped thereon).

Preferably the structural element, when raised off the ground with abase (or more than one base), is a pallet, whereby objects can bestacked or stored on the pallet for storage or transportation.

Preferably the width and length of the structural element corresponds toa standard pallet size. Typical pallet sizes include 1200 mm×1000 mm,1200 mm×800 mm and 800 mm×600 mm.

Preferably the pallet formed using the structural element and the atleast one base has a clearance afforded by the base to allow forks of aforklift truck or pallet truck to fit underneath the structuralelement,—e.g. between the ground and the underside of the structuralelement, or between stands of the base, and under the underside of thestructural element.

Prior art pallets have been formed using pairs of sheet material spacedapart by deformed sheet material, where the spacing and locations of thedeformed sheet material are such that forks of a forklift truck orpallet truck fit between the sheets. The present invention does notprovide that function—the pods of the structural element panel arelocated so as not to provide appropriate openings for forks of aforklift truck or pallet truck. In that respect the pods extend oversubstantially the entire extent of the sheets, save for perhaps theedges and the inevitable lost space between the circles (where circlesare provided). There is thus no space for penetration of a forkliftfork. Further the often staggered arrangement results in no throughpassageways whatsoever.

It is preferred that the pods are not stretched, dissected or deformedfor the purposes of forming the pallet, or for forming holes forforklift penetration. Instead the pallet of the present invention isprovided such that the lifting of the pallet with forks is from theunderside of the structural element and not via gaps or slots formed inthe structural element. As a result, loading on the structural elementremains externally applied and not initially internal. This ensures bothlayers of the structural element carry the full load with a compressiveelement, thus improving the strength of the pallet.

Preferably the or each base is shaped and located to extend from withinthe structural element. The base should have parts that are within thestructure of the structural element such that when it is subjected to aside load, its structure in combination with the structure of thestructural element, are exposed to the load and not solely the base.This adds to the strength of the pallet.

Preferably the base(s) of the pallet extends from the edges and/orcorners of the structural element. For instance, in the case of legs, aleg extends from each corner of the panel. For a typical pallet shape,this is a total of four legs. More legs can be provided—along the edgesor elsewhere—i.e. not on the edges or corners, or they can only beprovided not on the edges or corners. Spacing them widely, however,gives the pallet greater stability when loads are placed vertically ontothe pallet, especially at the edges thereof.

Preferably at least one edge of the structural element overhangs thebase, such that the length of the structural element is greater than thedistance between the outermost edges of the base in the directionperpendicular to that overhanging edge. Preferably the overhang islonger than the width of the leg's/base's bottom (still measured in thatsame direction). This then allows the base of a first pallet to stand onthe top of a second pallet, upon reversing its horizontal orientation,without nesting of the two pallets. This also allows the stacking ofpallets one above another by inverting one above another with the basesintermeshing. See FIG. 17. This can be a useful mode of stacking forwhere it is desirable to maintain a wider gap between the structuralelements of two stacked pallets than that achieved with nesting. Asshown in FIG. 13, however, the nesting function and wider stackingfunction can both be achieved with some designs.

Preferably the pallets, when stacked with the base stood on top of thestructural element of the pallet below it, are relatively rotated suchthat the overhang alternates from one edge to the opposite edge. Thiscan be done in repeating pairs. This maintains the same centre ofgravity for every two stacked pallets, and increases structuralstability when stacking without nesting.

Preferably the pallet has grooves or slots in the upper surface to allowthe locating of the base of a second pallet when stacking without fullnesting, i.e. only partial nesting.

The use of grooves ensures that the pallets are stacked in as stable,and non-sliding manner. It also makes the stacking uniform, thusmaintaining a consistent centre of gravity. The grooves are preferablyadapted to correspond in shape with the bottom of the base so as betterto prevent the sliding of the pallets relative to one another oncestacked.

Preferably the pallet is provided in combination with a base plate ontowhich the base of the pallet may stand. Preferably the base plate hasgrooves or slots into which the base(s) of the pallet can fit. As withthe grooves or slots in the top of the pallet, these can offer greaterstacking stability and support.

The use of a base plate allows the pallet to be used on conveyer belts,such as in a production line, without a need to invert the pallet (i.e.for placing the structural element's surface (which is more flat thanthe base) onto the conveyor belt). It also permits the pallet to beotherwise manoeuvred if the base plate is fitted with wheels or rollers.

Preferably the structural element, or the product incorporating thestructural element, has wireless, RFID, NFC or other electroniccommunication devices incorporated therein to allow remote electronicidentification. Preferably, where the structural element is formed frommetal or an electrically conductive material, the structural element usused as an aerial. The use of RFID and other contactless communicationtechnology is useful for tracking products, and particularly pallets,for transportation and inventory purposes. Where a wireless technologyis used, the need for the pallet to be facing in a particular directionfor the scanning of a barcode is removed.

Preferably the structural element includes a means of counterfeitprotection. More preferably, said counterfeit protection includes aspecifically identifiable material or element within the material whichforms the structural element. More preferably still, markings orwatermarks could be present on the inner surfaces of the sheets.

Preferably the structural element has no blind recesses—i.e. throughholes, whether straight or convoluted, are always present in each podand between the sheets if open at the edges. This reduces the weight ofthe pallet and also increases airflow around the object on the pallet,along with preventing liquids from gathering in the pods during storageand transportation and allowing more easy cleaning when the product isfor multiple usage (pallets can be disposable if made of cardboard orwood, but plastic pallets are often reusable in a pooling system, andpallets made using the present invention can likewise be reusable andthus being easily washable becomes beneficial.

The structural element may be used in other configurations too, bet theywith a flat panel or a curved panel, or both. These uses may include,but are not limited, to panels on vehicles or packaging, furnituresurfaces, building materials, platforms, etc.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

These and other features of the present invention will now be describedin further detail, purely by way of example, with reference to theaccompanying drawings, in which:

FIG. 1 shows a perspective view of a first embodiment of structuralelement according to the present invention—a cut-away slice of a largerelement;

FIG. 2 shows the structural element of FIG. 1 from a different angle;

FIG. 3 shows a sectional schematic of a diamond beam formed within thestructural element of the present invention;

FIG. 4 shows a further sectional schematic of the structural elementillustrating the action of forces acting on the structural element ofFIG. 1;

FIG. 5 shows a further schematic of forces acting on the structuralelement;

FIG. 6 shows a perspective view of a space frame, illustrating thecomparison between the present invention and a space frame, thecomparison being useful for understanding the strength underlying thestructural element of the present invention;

FIG. 7 shows a further schematic, in perspective view, illustratingforce lines on a pod of the structural element of FIG. 1;

FIGS. 8A to 8C show side schematics of the variable thicknesses of apanel using two sheets and the pods of the present invention;

FIG. 8D shows how the strength of the structural element can be altered;

FIG. 8E shows how the shape of the panel may be other than flat;

FIGS. 9A to 9H show plan view schematics of various potentialarrangements for the pods in a sheet of material used to form astructural element of the present invention. Other arrangements are alsopossible;

FIG. 10 shows a perspective view of part of an alternative structuralelement according to the present invention;

FIG. 11 shows a schematic perspective view of a cross-webbing in anembodiment of a structural element according to the present invention;

FIG. 12 shows a perspective view of a pallet incorporating a structuralelement according to the present invention;

FIG. 13 shows a perspective view of two pallets of FIG. 12 arranged suchthat they are nesting;

FIG. 14A shows an engineering drawing of legs of a pallet similar tothat shown in FIGS. 12 and 13;

FIG. 14 B shows the leg on a pallet, with removable skids;

FIG. 15 shows a perspective view of two pallets of FIG. 12 arranged suchthat they are stacked, and only partially nested due to grooves in thesurfaces of the structural element;

FIG. 16 shows a detailed view of the leg of a pallet of FIG. 12, plussome grooves for receiving a bottom of a leg of a further pallet;

FIG. 17 shows a side view of an alternative embodiment of pallet nestedin an alternative arrangement to FIG. 13 to a ghosted second pallet;

FIG. 18 shows a perspective view of the pallet of FIG. 12 stood on abase plate;

FIGS. 19 to 21 show alternative uses for a structural element accordingto the present invention.

FIGS. 22 to 24 show a further use—in the skids.

DETAILED DESCRIPTION OF THE INVENTION

Referring first of all to FIG. 1, a structural element 10 is shown. Thestructural element has sheets which form an upper plane 12 and a lowerplane 14. These planes sit parallel to one another at a defined distanceapart. On the surfaces of the upper plane 12 and lower plane 14 arecircular holes 18. These circular holes 18 are present on both planesand are arranged such that they are in-line with the opposing circularhole 18 of the parallel plane. The circular holes 18 are arranged suchthat they sit in rows. Each row is offset with the row of circular holes18 above it, such that alternative rows form a column of circular holes18.

Although this specific description describes upper and lower “planes”,it should be appreciated that the planes may be replaced with curvedsheets, thus they would then not be planar. For convenience, the word“plane” will nevertheless still be used.

Further, although circular holes are disclosed (and, later, squareholes), other shapes of hole are also possible, including regular andirregular shapes.

Extending from the planes into the void formed between them, i.e. towardthe opposing plane, are cones 16. These cones 16 define the pods and arecircular in this embodiment, with the base of each cone 16 (in theplane—defining the circular holes 18) defining a mouth for the cone thatis circular (albeit with rounded edges).

The other end of the cone—the apex of the cone 16, is truncated to forma frustum 20, the truncation being made parallel to the plane and thecircular hole 18. Rounded edges, however, are again provided at thatapex. The rounded edges reduce stress concentrations and provide acleaner appearance.

The resulting frustum 20 of the cone 16, in respect of the upper plane,extends from the sheet defining the upper plane 12, and it will line upwith the frustum 20 of a cone 16 extending from the sheet defining thelower plane 14. As such pairs of frustums 20 of pairs of cones 16 canmate to form a connection between the two planes with the circular holes18 in each plane being aligned.

In FIG. 1 there is also shown to be a hole cut into the frustums 20 ofthe mating cones and the hole of one of the frustums has a lip 22 whichextends as shown in FIG. 3 to allow a jointing, such as by crimping orwelding, of the two frustums 20. The apex or frustum 20 of the twojoined cones 16 are thus open at their middles and form a centralcircular hole 24. In this embodiment, since the mating cones are similarto one another (almost mirror images except for the lip 22), thatcircular hole 24 defines a medial plane, lying across a line paralleland equidistant to the upper plane 12 and lower plane 14.

Referring again to the cone in the upper sheet, the cone 16 is hollow,with, aside from the lip 22, the surface of the cone 16 laying generallyalong the line extending between the outer edge (the outer end of therounded edges) of the frustum 20 and the circular hole 18 (inner end ofits rounded edges) which forms the mouth. The area in which this surfacelays, being a cone, can be referred to as the generatrix 32 of therespective pod.

There are a plurality of these cones, and in this embodiment they areprovided in a regular array.

The sheets which form the upper plane 12 and lower plane 14, whenforming a structural element 10, can form an enclosed panel by having aside edge 26. The side edge 26, in this embodiment, is a junction wherethe sheets of the upper plane 12 and lower plane 14 are folded towardone another such that they are no longer parallel and extend so thatthey meet or overlap thus forming an edge 26. Alternatively a side sheetcan be attached to the edges of the sheet (either via, or to, foldedflanges). However, it is preferred to use the sheets for the upper andlower planes since that reduces the component count of the finalproduct.

Techniques for manufacturing the structural element and forming thecones 16 and 5 edges 26 are discussed later in this document. However,suitable methods include press-forming or roll-forming, amongst others.

In FIG. 2, an alternative viewing angle is provided such that a row ofcones 16 can be seen to have been vertically cross-sectioned, i.e.through from the upper plane 12 to the lower plane 14, to provide a viewof the structure formed by the mated cones. Here it is seen that thesheet forming the upper plane 12 and the generatrix 32 of its cones 16form a triangular shape along the cross-section line. The apex of thistriangle is truncated to form a further frustum since the cones, andparticularly circular holes 18 at their mouths, are spaced apart by asmall percentage of the diameter of the circular holes 18 (in thisexample, about 11% of that diameter, although other embodiments mayrange from between 1 and 20%).

The base of this truncated triangular shape is abutted by the base of asimilar truncated triangular shape formed by the sheet of the lowerplane 14. The combination of these shapes is a shape similar to that ofa diamond. Since this diamond shape extends parallel to the planes ofthe structural element (the panel), it forms a diamond beam 30. Thediamond beam 30 is a result of the negative space left from the surfacesforming the cones 16 spanning the area between the upper plane 12 andlower plane 14.

There are similar diamond beams 30 formed throughout the structuralelement 10 in the space between the cones 16. In this embodiment, thisis a honeycomb arrangement, and some of these are shown by centre lines34. The centre lines 34 show the vertical axis of the diamond beam 30between the apices of the upper 12 and lower 14 planes which aretruncated. Since the circular holes 18 are arranged in a staggeredarrangement in this example, the centre lines 34 define hexagonalcells—the honeycomb structure. This is an efficient arrangement for thediamond beams. If the circular holes instead align in a grid, however,then the centrelines would likewise define a regular grid, with squareangles, rather than 120° angles, between the “beams”.

For this embodiment, since the pods are round, the diamond beams 30extend as shown with their geometries varying—depending upon at whichpoint along the beam thereof you are looking at within the grid orhoneycomb of the structural element 10.

The side edge 26 is seen again in FIG. 2 and this again shows that wherethe edge of the structural element 10 is formed to form a panel, thecones 16 are not present in that zone of the sheet. As a result, no podor cone is vertically truncated or otherwise distorted by the forming ofthe edges of the panel. This ensures that the diamond beams 30 are fullyformed between all of the adjacent pairs of cones 16 and there is noweakened cone within the structural element. It also ensures that ifedged panels are formed, then the edges of that panel will all be solidand smooth-walled. This can assist with functions such as the joining toother panels, forming a seal, or forming a smooth or regular edge formanual handling purposes.

Although the term diamond beam is used throughout the description of theinvention, it is important to note that the geometry of the structuralelement is defined by various factors, such as manufacturingrequirements, material choices, and visual geometry, i.e. the shapes ofthe pods, and as such it is a more complex shape than a strictreplication of a geometric diamond beam. However, the resulting shape ofthe beams within the panel formed between the pods thereof, cannevertheless be effectively referred to as a diamond beam 30 since thecreated shape does share structural characteristics similar to those ofa geometric diamond beam, recognising though the reduction in strengththereof resulting from the truncation of its apices.

A brief explanation of force loading within the beam as a result ofloading applied to the panel, and thus also the diamond beam 30 of thepresent invention, is discussed below, with reference to FIGS. 3 to 7.

The diamond beams 30 created in the negative space throughout most ofthe structural element are important for the strength of the structuralelement 10.

Referring to FIG. 3, a single section through a diamond beam 30, similarto that which may be found in a structural element according to thepresent invention, is shown. The truncations at the apices are reducedcompared to that of FIGS. 1 and 2 for the purpose of this illustration,which reduction can result from the circular holes 18 being packed moreclosely together, or from using other hole shapes or arrangements, suchas the close-packed squares of FIG. 10.

In this example, force lines 40 are due to a compressive load on theupper plane 12 of the structural element 10 which is acting on the topapex of the diamond beam 30. The force lines 40 show the tendency of theload to act on the diamond beam 30 attempting to deform it by theresultant vertical forces and horizontal forces. To resist thehorizontal forces ‘opening’ the diamond beam, apex force lines 44represent the bracing resistance to deflection from the upper plane 12and lower plane 14 which joins a braces surface between the diamond beam30 apices. Reactive force arrows 42 show the restraint afforded by thetruncated edge 20, which in turn forms the edge of other diamond beams30. Thus the force lines 40 acting horizontally to open this diamondbeam 30, are being transferred to diamond beams 30 within the largerarea of the structural element 10. The lip 22 also forms a level ofbracing against the force lines 40 acting horizontally, since the lip 22is a horizontal piece, and in this version it is double thickness, andwith a crimped part providing a L-beam type formation, thus offeringgood resistance to flexure and bucking. The resistance to verticaldeformation from a load represented by force lines 40 is granted by thebracing to the apex force lines 44 and restraint resulting in thereactive force arrows 42 since a vertical deformation would require ahorizontal deformation. In addition, the lower plane 14 would transferthe forces to other diamond beams 30 within the structure, and give aresultant vertical force 46 resisting the load.

FIGS. 4 to 7 further show the transferral of the forces within thestructural element 10 between cones 16 and diamond beams 30 which grantthe structural element its strength and resistance to deformation.

The transferral of forces in such a manner can be compared to a spaceframe 60 as shown in FIG. 6. A space frame transfers loads along thelength of the beams 62 of the space frame 60 such that a single pointload acts on multiple beams 62.

A comparison of such a transfer to the structural element 10 of thepresent invention can be seen in FIG. 4, where diagonal force lines 50represent the transferral of a load through a structure from upper apex64 to lower apex 66 of adjacent diamond beams 30. The diagonal forcelines 50 represent the typical beams 62 of a space frame 60.

The forces, in reality, would travel along and across the surfaces ofthe cones 16, to transfer a force between the upper plane 12 and lowerplane 14, thus further spreading the loads. The area of forcetransferral 52 uses hashed lines to represent the area between diagonalforce lines 50 and the route which the force would travel along thesurface of a cone 16 if subjected to such a load. This force transferralcan be seen in FIG. 7 where the area of force transferral 52 is shownnot to follow a single diagonal force line 50, but travel along thesurface of the cones 16. This shows the equivalence of the transferralof forces in the structural element 10 of the present invention comparedto a space frame 60.

Referring to FIG. 5, an advantage of the structural element 10 is shownby cross braces 54, these are formed when diagonal force lines 50 cross.Cone force lines 56 provide a more probable representation of the routeof forces through the structural element, although still result in crossbraces 54 from the resultant force transferral. The result of thesecross braces 54 is the transferral of the forces in multiple directionsbetween the upper apex 64 and lower apex 66 of the diamond beams 30 andthroughout the structural element 30 creating a matrix of compressiveand tensile forces within the element when a load acts upon it. Thisstructure thus offers the significant strength characteristics of aspace frame, but without the complexity of joining multiple framemembers or struts together to form that space frame.

A comparison to a space frame has been described here. However, whereasa space frame has a relatively straightforward predictability in termsof calculating its strength properties, with the structural element ofthe present invention the transferral of forces can be much morecomplex, especially where additional beams, ridges or surfaces are usedin the structure of the pods or sheet materials This is since thestructural element comprises load bearing surfaces between the “struts”,such as the planes and cones as opposed to just beams and struts.However, for the purposes of demonstrating the generic structuraladvantage of the present invention, particularly when compared to otherstructural elements which may use cross bracing or sheet materials intheir structure, the comparison to space frames is of use and relevance.

The structural element 10 can be formed from a pair of sheets ofmaterial in a pressing machine. The machine punches the material forforming the cones 16. This might be a single sheet that is then foldedto form the two sheets in opposition to each other, or more usually—forreducing machinery cost—it is two separate sheets. As such a first sheetis so formed and another sheet is likewise punched with its cones 16,this time extending toward the original sheet, and the two sheets andopposing cones are then joined at the truncated edge 20 of the cones 16.

The two sheets can be concurrently pressed and then joined in a laterprocess, or such that two continuous sheets are fed into a singlepressing and crimping or welding machine to be made in one pass. Eitherway, the manufacturing of the structural element may be part of a highspeed manufacturing line, e.g. taking the sheet(s) off one or more rollof sheet material.

Although pressing machines are referred to, any appropriate materialmanipulation methods may be employed. These may include but are notlimited to stamping, moulding and high temperature cutting and thechosen process may depend on the material used to form the structuralelement. Various metals are suitable for the structural elementmaterial, and many of them have many of the above processes as beingapplicable for their processing. Steel is a preferred material, as isaluminium. Preferably steel can be coated with a corrosion-resistantfinishing material that is applied to or impregnated into its surfaces.This adds to the longevity and reusability of the structural element.

An advantage of metals is that a number of them have very wide operatingtemperature ranges, typically including safe upper temperature limits ator above the range of 100° C. to 400° C. They can also besterilised/autoclaved, and are non-flammable and hygienic, especiallystainless steel.

The material to use is not limited to metal, as other materials may beused instead, these include plastics, paper or fibre based materials,graphene, composites, alloys, glass or glass fibre, ceramics, carbonfibre, plywood and laminated wood, chip board and plastic woodcomposites. The skilled person will also be aware of other appropriatematerial, depending upon the mode of manufacture to be used, be itforming or fabrication or moulding.

The material between the faces of the truncated edges 20 of the conescan be removed before or after joining the cones together, leaving acentral circular hole 24. The removal of the material can thus be partof the first pressing process to increase efficiency, or it can be donelater. It is not an essential step, and as such it can even be omittedif low weight is less critical. Nevertheless, the removal of thematerial will reduce the weight of the structural element 10 where thisis a concern. In addition there may be advantages for having holeswithin the structural element for purposes such as ventilation. Theremoved material can also be recycled. However, if the material formingthe faces of the truncated edges 20 remains, it can add additionstrength to the structural element providing an additional surface forforces to be transmitted through, especially edge forces or skew forces.

The edges 26 of the structural element may be formed by bending of thesheet at each edge toward the opposing sheet and sealing or joining. Thesealing or joining used at the edge, along with the joining of thetruncated edges 20 of the cones 16 can use a number of material joiningtechniques such as crimping, riveting, welding, brazing, moulding,stapling, gluing, etc. The joining technique used can depend on thematerial used and the level of seal required. Materials can even befolded over one another in a loose-crimp or otherwise slotted ormechanically zipped together to form the structural element.

When forming the structural element from sheets, the thickness of theresulting structural element may be varied to alter the strength of thestructural element. FIG. 8A shows a cross section of a sheet material 70with a total thickness 72. This is a single thick sheet. Thisarrangement has a given strength. In FIG. 8B it can be seen that thesheet material 70 is cut in half to provide two half thicknesssheets—i.e. the same amount of material, but from these two sheets it ispossible to form the planes of the structural element 10, and also thepods or cones 16. The thickness 72 of the overall structure can thus beincreased to increase the overall vertical load carrying strength of thestructural element 10.

Referring then to FIG. 8C, the cones are stretched further—throughlarger circular holes 18. This can further increase the strength,although there will be limits to how far the material of the sheets canbe usefully stretched. As such, there is typically a preferred maximumcone-angle of 75° from the plane, although angles between 45 and 80°would be likely to be used.

Increasing the thickness 72 of each sheet can provide thicker walls forthe cones 16 too. This can be used to allow the distance between the twosheets (the plane distance 74) to be increased further, since there ismore material which can be stretched to form the cones 16.

The variation in cone size or depth can allow the structural element tobe altered for various situations where dimensions or strengths arerequired. For example, where a sheet material 70 with a thickness 72 of0.2 mm to 0.4 mm is used, the stiffness of the structural element 10 canbe enhanced by increasing the plane distance 74 from 25 mm to 30 mm, orby reducing the diameter of the circular hole 18 (the directrix 76) from50 mm to 40 mm. See FIG. 8D. Having the beams closer together ordeepening them makes them typically more resistant to bending.

Other ways to change the strength of the structural element 10 mayinclude varying the distance apart of the cones along the plane of thestructural element, such that the diamond beam 30 has a more or lesstruncated apex. The cone 16, which has been described so far as acircular cone, can alternatively be changed to a different array ofshapes. For example, see FIGS. 9A to 9H, which show various arrangementsfor the holes in the plane, and therefore various punched shapes forforming the pods in the sheet material. The first circular embodiment isshown in FIG. 9A, where circular holes 18 are arranged in offset rows.Other examples include various sized holes, triangular holes, squareholes, hexagonal holes, elliptical holes, a combination of differentshaped holes or indeed any number of polygons in any arrangement.

Where the holes are formed out of the sheet, the shape of the hole mayhave limits in terms of the degree of stretch available from theoriginal sheet material.

The shape of the hole will help to determine what shape pod will beformed. For instance, as previously described, the circular holes 18 ofFIG. 9A or FIG. 9B will typically form regular cone shaped pods.

There may be a need to add webbing or corrugations between adjacent podsto some formed shapes to increase the strength of the pod.

FIGS. 10 and 11 show an alternative embodiment of the structural element80 according to the present invention. In this alternative structuralelement 80, the pods are similar to that as shown in FIG. 9C. Here thepods are square pods 82 and they are arranged in parallel rows andcolumns. Such an arrangement results in the diamond beam 30 being of agenerally uniform sectional shape along the edge of each individualsquare pod 82. This arrangement results in the forces being more similarto that of a space frame, since between the intersections, the diamondbeams are uniform for the transmittal of forces.

In this embodiment, webbing 84 has been formed at the corners of thesquare pods 82, this is helpful to increase the resilience of thestructural element 80 to the twisting forces 86 which it may besubjected to. It also allows a deeper form for the pods since lessstretching becomes necessary at the corners of the pods. FIG. 11illustrates this webbing. It can be formed as the pod is formed (thecut-back flanges are only cut back for illustrative purposes)—or it canbe fitted after the pods are formed as a post-form attachment. Theformer is preferred due to the reduced component count and improved easeof manufacture.

FIG. 10 also shows within the grid of pods an area with a larger pod.This larger pod occupies the space of four normal pods (although it canbe smaller or larger if preferred). By occupying a space equivalent to awhole number of normal pods, it can readily be formed without alteringthe structure of the surrounding pods.

The larger pod is for forming or receiving a leg of the structuralelement, thus allowing the integral formation of legs at the undersideof the structural element, e.g. to offer the structural element in theform of a pallet. The legs can support the rest of the structuralelement above the ground.

To form the leg, the upper sheet is deformed with a large pod, whereasthe lower sheet is deformed in an opposite direction to its normal withthe deformed upper larger pod still engaging a part of the podunderneath it (the oppositely extending pod of the lower sheet). Thesetwo pods thus then form a strong leg for the pallet. For or more ofthese might be provided in a structural element if it is to be apallet—each being at or near corners of the structural element.

FIG. 12 shows an alternative design of pallet 100 which is formed from apanel 119 utilising the pod structure of the present invention—similarto the structural element 10 as seen in FIG. 1. The pallet comprises apanel 110 which is an enclosed structural element with panel edges 124.The panel 110 can accept objects or loads on its upper face 112, whichis in this example the upper plane 12 of the structural element 10. Inthe panel 110 are the cones 16 which pass through a half thickness ofthe panel 110 to mate against corresponding cones extending upwards fromthe lower plane.

Pallets of this type can be used for the transportation of objects,since it allows easy movement with a fork lift truck due to the elevatedplatform and space underneath for forks thereof. They are also typicallyprovided as a uniform or standardised dimension product, such that loadlocation requirements can be predetermined. This also makes them veryuseful in stores and warehouses and transport vehicles, whereshelves/load-bays can be designed to fit or receive a pallet.

Raising the panel 110 off the ground are legs 120. These legs 120 areshaped differently to the full cup shape of FIG. 10, and instead arehalf-cup shapes—similar to a cup which has been sectioned in halfvertically, revealing open edges.

The legs 120 are aligned to the load-bearing surface of the pallet (thestructural element part, or the panel) such that the top of the cupshape is flush with the upper face 112 of the panel 110 and the openedges of the cup are flush with the lower panel edge 124. This meansthat the legs 120 sit inside the periphery of the panel 110. The sidesof the pallet thus have recesses in them—at the legs.

Forming the base of the legs 120 is the bottom of the cup which has agenerally semi-circular shape in plan. It also bends upwards to be aconcave base when viewed from below, it thus extending upwards slightlyinside the cup of the leg 120. This reduces the load area on the groundand also cooperates with a detail in the upper surface of a secondidentical pallet, as explained below.

There are four such legs in this example, although more legs can beprovided if desired.

The tops of the legs 120 are wider than the bases of the legs 120. Assuch the sides of the legs are tapered. The legs 120 as shown also donot intersect any of the cones 16, but instead, where the leg 120 wouldinterfere with the cones 16, the cones 16 have been omitted from thepanel 110.

The profile of the leg 120 which extends through the panel in thisexample is generally curved, much like a semi-circle, as with the bottomof the cup, but here it is optionally more pronounced to approximate athree sided polygon with rounded edges. However any shape may be usedwhen forming the cup shaped legs 120—for the top or bottom of the leg,and in-between, although a smooth taper from top to bottom is preferred.

FIG. 13 shows two pallets 100 which are stacked on top of one another.The pallets 100 are arranged such that the legs 120 are aligned whenviewed from a plan view. Since the legs 120 are shaped as half cups withno top, and the sides of the legs 120 are angled such that they aretapered toward the base, with the preferred smooth taper, the legs 120of a lower pallet 100 allow the adjacent legs 120 of a pallet 100 aboveit to partially sit inside it. This allows the pallets to nest whenstacked, and each additional pallet 100 added to the stack will nest inthe pallet below it.

Nesting allows pallets to be stacked, particularly when they are not inuse, and occupy less space vertically than two un-nested pallets. Thiscan be useful for the transportation of the pallets, or for theirstorage, allowing more pallets to be placed in a single space.

The nesting also reduces horizontal movement or sliding of stackedpallets relative to one another since they are horizontally constrainedbetween each other.

The degree of nesting can be determined by the shape of the legs.Changing the shape or adding a ridge thereon can stop one leg fromslotting further inside another.

The legs can be shaped such that a panel 110 of a pallet 100 sitsdirectly on top of a panel 110 of the pallet below it. This can be ofsome use when needing to reduce space occupied by stacked pallets and itwill also allow for the transfer of forces between structural elementpanels 110—if a greater load bearing capacity of panel was required.More common, however, is a requirement to maintain a larger gap betweentwo stacked panels, perhaps to ensure that forks are able to fit betweennested panels, or otherwise to allow their simple separation. After all,it is likely to be useful if pallets do not become difficult to un-nestfrom one another.

FIG. 14A shows in more detail an arrangement for a leg 120 and thenesting of an adjacent leg 122 which sits within the tapered insidesurface of the leg 120. In this arrangement, the adjacent leg 122 innested fully such that the panels 110 are in contact. It is also shownthat the top of the leg 120 can sit within a larger fitting panel 124than the top profile of the leg in FIG. 13—three pods wide, not two.

The leg 120 may be separately moulded and then joined to the overallframe 110 by welding, brazing or other known techniques. Alternativelyit can be of a design that can be pressed out of the sheets, as withFIG. 10. An arrangement where it is positioned in the corner of a palletis shown in FIG. 14B. As can be seen there are four such legs, each in asidewall/corner of the pallet. The pallet has square pods in its toppanel rather than round ones. Additionally, the bottoms of the legs canconnect with skids.

The forces which are exerted on the leg 120 can be transferred to thestructural element of the panel through nodes 126, which are the apicesof diamond beams within the panel 110. Therefore there is an efficienttransfer of forces through the legs 120 into the structural element.

The legs 120 of the pallet 100 shown in FIGS. 12 and 13 do not all sitat the four outermost corners of the panel 110, but instead two of thelegs are inset from this edge, resulting rusting in an overhang 130 onone edge of the pallet, and the others are at an end, but located on aside, rather than symmetrically at the corner. Other positions arepossible. However, FIG. 15 shows that due to the overhang 130 and insetlegs, when two pallets 100 are stacked with the overhang 130 at oppositeedges, if the panel edges 124 of the two pallets are kept verticallyin-line from a plan view, the pallets 100 may stack without fullnesting. Further pallets can be stacked in this manner, and since theoverhang 130 alternates sides, this mode of stacking maintains astraight stack since the centre of gravity is not eccentric over lowerstacked pallets.

Such stacking without nesting may be useful when objects shorter thanthe legs are loaded onto the pallets, or when a small number of thepallets are to be stored or moved—the gaps between the panels readilyreceive forks of a forklift.

An additional feature of the pallet 100 that is useful when stackingpallets without full nesting, is the groove—here a semi-circularcircular groove 132—present adjacent to the top of the legs on the upperface 112 of the pallet 100. There are four of them—one by each leg top.The circular groove 132, in each case, is an indentation in the topsheet shaped such that the base of the legs 120 (with its concavedetail) can locate within the circular groove. This allows, whenstacking, a guide to ensure the legs 120 are located in the ideallocation to ensure the maximum stability for the stacked palletstructure. Further, since the pallet may be formed of a rigid materialwith a smooth surface (e.g. a metal), there may be an increased tendencyfor pallets to slide when stacked or nudged. The circular grooves 132have the added feature of reducing sideways movement of the pallet 100since they add an additional vertical movement necessary for anysideways movement, and since they are not linear, they encapsulate theleg bases.

Although a circular groove is shown, any shape which relates to the baseof the leg of the pallet may be used. In particular, other shapes arepossible which will provide stability.

The encapsulation function is also beneficial—i.e. for the prevention ofslippage through some or all grooves simultaneously. This may beachieved with blind slots, angular slots, or differently orientatedgrooves at the respective leg positions around the surface of thepallet. In the present example, this already occurs since thesemi-circles face opposite direction on opposite sides of the pallet.

Alternatively a rough surface may be applied at the points of contact toreduce the tendency for horizontal relative movement.

The present invention can also comprise such a pallet fitted withseparate skids. Many conventional pallets have skids to form the bases.For example, see the arrangement as shown in FIG. 16. This skid plate136 extends between two legs 120 and has a groove similar to that of thecircular groove 132 for locating the leg 120 onto the skid plate 136.The leg 120 may then be attached to the skid plate 136 by joiningmethods such as welding. Other leg base and groove designs are naturallypossible, as discussed above for the grooves in the upper surface of theplate.

The skid plate 136 allows the pallet 100 to be used in situations wherelegs 120 may cause a point load and damage the surface on which they arestood, or where legs 120 would be impractical, for instance on aconveyer belt of a factory where pallets may have goods loaded directlyonto them. The use of a skid plate 126 also allows the pallets 100 to bemanufactured with just legs 120 and the skid plates 136 addedafterwards, thus removing the need for two pallet manufacturingprocesses. The skid plates 136 can also be of a different material tothe pallet 100, or have a softer material bonded to their underside,this may be useful where a harder material of a pallet may damage asurface, but a soft base, such as wood, can reduce the likelihood ofscratches on floors due to pallets being slid about.

The skid plate 136 would mean that nesting of the pallet was no longerpossible, however, FIG. 17 shows an alternative arrangement for nestingpallets which could apply when a skid plate 136 is installed. Here, dueto the overlap 132, a pallet 100 can be inverted relative to anotherpallet so that the legs 120 sit next to the adjacent legs 122 of theother pallet. This can provide the same reduction in height when nestingtwo pallets as the legs 120 without the skid plates 136. In additiongrooves can be present on the underside of the panel 110 for locatingthe legs 120 or skid plates 136 when inverted nesting the pallets. Thismode of nesting can likewise be used without the skid plates.

The present invention may even reside in the design of a skid plate 136,See FIGS. 22 to 24. After all, the elongate skid member may be formed asa structural element using the pods structure, it thus being astructural element according to the present invention. As shown in FIG.22, the skid can be formed with more than one section of structuralelement, here attached to one another along a foldable lower sheetmember. The sides are angled and through folding and welding of thestructural members together, the U shaped skid can be formed. This canthen be attached to a pallet top, such as one that is in accordance withthe present invention as shown in FIG. 23.

FIG. 23 shows two skids on the pallet, one being recessed from an end toleave an overhang, as previously discussed. FIG. 24 instead shows threeskids—two end skids and a middle skid. Other arrangements are alsowithin the scope of the invention. FIG. 24 also shows the pods in anon-staggered, grid-like array. This is another option for the circularholes 18.

Due to the advantages afforded by the legs 120 with and without the skidplates 136, it may be desirable to have a pallet which has the benefitof both. FIG. 18 shows a base plate 140. This base plate either has skidplates 136 mounted to it, so a pallet can be put onto the skid plates,or it receives a pallet with such skid plates on it. It may even beprovided without skid plates between the pallet and the base plate—thebase plate thus then having, preferably, the above-described groovefeature for directly receiving a pallet with legs. This allows thepallet 100 to be placed on the base plate 140 and the base of the feet120 be secured thereon by the grooves in the skid plates or in the baseplate 136.

The base plate 140 may be used on production lines with conveyer beltsand allow the pallets to move along without risk of the legs 120 lackingthe surface area to be sufficiently carried by the conveyer belt.

The pallets can be manufactured from two sheets of material which arepunched to form the necessary shape and removing the space for the legs120. This can be one pressing motion with a continuous sheet of materialbeing passed through the machine and cut up later into panel 110 sizedblocks. The pressed sheet is then joined to an opposing pressed sheet atthe cone bases.

The legs 120 can even be extruded from the sheets of material, althoughif thicker material is required to provide strength, or if a greaterform height than that which would be safely achievable from the sheetsis required, then a separate joining method will be preferable for thelegs.

Many materials can be used for forming the pallets 100, although metalsheet materials particularly suit the process. Metals also have theadded benefit of being easily cleaned and sterilized. This can beimportant when transporting goods on pallets to countries where thereare strict laws about imports, such as those where wooden pallets wouldbe prohibited due the possibility of carrying insects or foreign matter,or in general for food stuffs. Stainless steel, aluminium and plasticsmay be useful materials in that respect due to their sterilisability,and thus reusability. However, many other materials are also reusable orrecyclable—of benefit in other sectors.

The weight of a pallet can also be important, and the sheet materialoffers the ability to produce a pallet of great strength with minimalweight. The cones 16, with the centres removed also reduce the weight ofthe pallet. For example, whereas a conventional wooden pallet may weighabout 10 kg (for a typical 600×800 pallet), an equivalent pallet of thepresent invention, made of 0.24 mm steel, taken off coils of sheet steeland pressed to the required shape with the pods as shown in FIG. 12,which pallet will offer a similar safe working load capacity to that ofthe prior art timber one, may weigh only 1.8 kg.

It is preferred that for a 1200×800 pallet, the weight of the pallet,when utilising the present invention, does not exceed 4.0 kg.

The thickness of the sheets of steel preferably do not exceed 1 mm, butmore typically will not need to exceed 0.4 mm or even 0.3 mm. 0.24 mmhas been found to be adequate for standard pallet sizes.

In terms of the thickness of the panels, where the sheets are made ofmild steel, a sheet having a thickness of 0.25 mm can theoretically bestretched safely to provide a panel having a depth of about 40 mm. It ispreferred that the pods from such sheet material do not exceed a depthof 25 mm. In general this equates to a preferred pod height notexceeding 10× the thickness of the sheet material.

The cones 16 in the pallet 100 also have a number of other features.They allow the circulation of air around the object on the pallet, thiscan be important when consignments must be heated or cooled to certaintemperatures before travelling. This is commonly useful in the logisticsindustry, especially in the cold chain where the speed of bringingconsignments down to the desired temperature affects operating costs andconsignment quality. With the pods of the present invention's structuralelement, this airflow is achieved substantially evenly across the entirepanel, especially with square or other high-packing-density pod shapessuch as triangles and hexagons. The cones 16 also ensure that if liquidsfall onto the pallet, or they are left outside in the rain, no liquidcan gather in pockets in the pallet. This can also apply to dirt, whereit will be washed through the holes of the pallet, and, if necessary,can easily be cleaned by spraying water.

The cones 16 also provide an uneven surface which softer objects carriedon the pallet may sink into and thus be more secure on the pallet.

It is preferred that in any design that the apex of the beams/borders ofthe top-surface holes 18 have a rounded edge so that it is smooth toprevent cutting, tearing or other “sharps” damage to goods stored orlocated on the pallets.

Although a specific use in pallets has been discussed, the structuralelement may be used in any number of further applications. FIGS. 19 to21 gives some further examples of the use of the structural element,although the use is not limited to these.

FIG. 19 shows a box, which may be formed of cardboard or any othersuitable material which has the internal structure of the structuralelement. This will provide additional strength to the box and may allowadditional stacking of boxes, which may make transport easier and resultin fewer goods damaged in delivery due to boxes being crushed.

Corrugated sheets in general can likewise benefit from the presentinvention's structure, e.g. using a touch adhesive on the internal facesof the two pod-formed sheets.

The structural element can includes a means of counterfeit protection.When considering card, a specific paper grade or an injected chemicalsignature in the pulp can be utilized. A particular or distinctive imageor pattern, etc. can be printed on the inner, unseen, surfaces of thesheets to further provide some counterfeit protection. Such techniquescan provide a subtle, or difficult to reproduce signature which can beused to identify the structural element.

FIG. 20 is a skateboard where the structural element is used to form theboard or platform, this uses the advantages of the structural element ofthe present invention to create a lightweight yet strong platform, whichcan reduce the weight of the skateboard.

FIG. 21 is a lorry where the trailer is formed from panels of thestructural element according to the present invention. This can providea strong side of a lorry trailer, protecting the loads inside and also,due to the shape of the cones on the surface of the panels, may reducepressure drag past the sidewalls of the vehicle as the vehicle movesalong the road. This is achieved since the pods can creating a turbulentflow on the panel's surface, thus and reducing the wake of pressuredifference. This is similar to the dimples of a golf ball. For this itis preferred that the cones or pods are generally rounded, or relativelyshallow, i.e. not exceeding 25% of their maximum outer diameter ormaximum outer linear dimension,

The present invention has therefore been described above by way ofexample. It provides a structural element (10) with an upper plane (12)and lower plane (14) which are parallel and deformed along their planeat intervals by pods (16) which extrude toward the opposing plane withtheir internal faces mating to one another.

The invention claimed is:
 1. A structural element in the form of astructural panel, the structural element comprising: two outer sheetsthat act as the tensile and compression chords, with the two outersheets comprising multiple inwardly orientated pods throughout thestructural panel, the inwardly orientated pods having apexes that arejoined together, which pods have a close proximity to one another inorder to be mechanically interdependent creating a double depthspace-frame lattice type matrix where loads placed on a surface of thestructural panel are resisted and transferred through the chords andwith the inwardly orientated pods acting as interconnecting diagonalbraces such that the loads are transmitted along the surfaces of thepods in multiple directions and distributed throughout the structuralelement, wherein walls of a side cross-section of joined pods formdiamond beam formations with adjacent joined pods such that multiplediamond beam structures are formed in the structural element in thenegative spaces immediately between pairs of joined pods, wherein thewalls of the side cross-section of each of the inwardly orientated podscomprise straight sides, wherein the pods are frusto-conical in shape,and wherein mouths of the pods are round and arranged in rows, adjacentrows being staggered to define a grid with centerlines for the pods at120° from one another, and the pods being spaced apart between 1 and 11%of the pod diameter.
 2. A structural element according to claim 1,wherein the floor of the pod is circular.
 3. A structural elementaccording to claim 1, wherein a part of the floor or base of one or moreof the pods is removed leaving a flange.
 4. A structural elementaccording to claim 1, wherein one or more of the pods has more than oneside composed of a flat area.
 5. A structural element according to claim1, wherein the sides of the pods are at an angle between 30° and 80°from the plane of at least one of the two outer sheets of the structuralelement.
 6. A structural element according to claim 1, furthercomprising foam being positioned between the outer sheets to offerinsulation or soundproofing properties.
 7. A structural elementaccording to claim 1, wherein the inwardly oriented apexes are gluedtogether.
 8. A structural element according to claim 1, wherein thestructural element is made from two sheets of a fibrous or cellulosematerial such as paper or card.
 9. A structural element according toclaim 1, further comprising a specifically identifiable material orelement, or a chemical signature, within the identifiable material thatforms the structural element.
 10. A structural element according toclaim 1, further comprising markings or watermarks on the inner surfacesof the outer sheets.
 11. A structural element according to claim 1,further comprising a wireless, RFID, NFC, or electronic communicationdevice incorporated therein to allow remote electronic identification.12. A structural element according to claim 1, wherein the mouth of eachpod and the apex of the beams have rounded edges.
 13. A structuralelement according to claim 1, wherein the pod height does not exceed 10×the thickness of the outer sheets' material.
 14. A structural element inthe form of a structural panel, the structural element comprising: twoouter sheets that act as the tensile and compression chords, with thetwo outer sheets comprising multiple inwardly orientated pods throughoutthe structural panel, the inwardly orientated pods having apexes thatare joined together, which pods have a close proximity to one another inorder to be mechanically interdependent creating a double depthspace-frame lattice type matrix where loads placed on a surface of thestructural panel are resisted and transferred through the chords andwith the inwardly oriented pods acting as interconnecting diagonalbraces such that the loads are transmitted along the surfaces of thepods in multiple directions such that the load is distributed throughoutthe structural element, wherein walls of a side cross section of joinedpods form diamond beam formations with adjacent joined pods such thatmultiple diamond beam structures are formed in the structural element inthe negative spaces immediately between pairs of joined pods, whereinthe walls of the side cross-section of each of the inwardly orientatedpods comprise straight sides, wherein mouths of the pods are triangularand are arranged with interfacing sides so as to occupy substantiallythe whole of an upper reference plane of a first of the two outersheets, leaving a grid for the upper reference plane where the pods meetat upper edges of the pods.
 15. A structural element according to claim14, wherein the diamond beam structures are elongated to define a gridof diamond beam structures.
 16. A structural element according to claim14, wherein the structural element is made from two sheets of a fibrousor cellulose material such as paper or card.
 17. A structural elementaccording to claim 14, wherein the mouth of each pod and the apex of thebeams have rounded edges.
 18. A structural element in the form of astructural panel, the structural element comprising: two outer sheetsthat act as the tensile and compression chords, with the two outersheets comprising multiple inwardly orientated pods throughout thestructural panel, the inwardly orientated pods having apexes that arejoined together, which pods have a close proximity one to another inorder to be mechanically interdependent creating a double depthspace-frame lattice type matrix where loads placed on a surface of thestructural panel are resisted and transferred through the chords andwith the inwardly oriented pods acting as interconnecting diagonalbraces such that the loads are transmitted along the surfaces of thepods in multiple directions such that the load is distributed throughoutthe structural element, wherein walls of a side cross section of joinedpods form diamond beam formations with adjacent joined pods such thatmultiple diamond beam structures are formed in the structural element inthe negative spaces immediately between pairs of joined pods, whereinmouths of the pods are intermeshing regular hexagons and are arrangedwith interfacing sides so as to occupy substantially the whole of anupper reference plane of a first of the two outer sheets, leaving a gridfor the upper reference plane where the pods meet at upper edges of thepods.
 19. A structural element according to claim 18, wherein thestructural element is made from two sheets of a fibrous or cellulosematerial such as paper or card.
 20. A structural element according toclaim 18, wherein the mouth of each pod and the apex of the beams haverounded edges.